test(source/alloydb): create MCP integration tests

[anubhav756]

Overview

This PR adds the mapped integration tests for AlloyDB tools using the native MCP harness.

Changes

• Created tests/alloydb/alloydb_mcp_test.go to test database listing and cluster operations over the native /mcp pathway.
• Achieves parity with coverage from the legacy alloydb_integration_test.go.

Checklist

• Ensure the tests and linter pass

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the AlloyDB integration tests to leverage a newly introduced native MCP JSON-RPC harness. This change standardizes how tools are invoked and their responses are processed within the test suite, leading to a more robust and maintainable testing framework. The update ensures that all AlloyDB-related tests interact with the tool endpoints through a consistent and unified interface.

Highlights

• Migration to Native MCP JSON-RPC Harness: The AlloyDB integration tests have been migrated from direct HTTP API calls to a new native MCP JSON-RPC harness, centralizing tool invocation and response handling.
• Simplified Tool Invocation: Replaced manual HTTP request creation and response parsing with helper functions like tests.GetMCPToolsList and tests.InvokeMCPTool for consistency.
• Updated Response Handling: Modified test logic to parse responses from the new mcpResp structure, including specific handling for JSON-RPC errors, application-level errors, and successful results.
• Removed Redundant Structs: The ToolResponse struct, previously used for parsing generic tool responses, was removed as its functionality is now handled by the new harness.

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[gemini-code-assist]

Code Review

This pull request refactors several AlloyDB integration tests to use a new tests.InvokeMCPTool helper function and a standardized mcpResp structure for handling tool invocation responses. This includes updating runAlloyDBToolGetTest, runAlloyDBListClustersTest, runAlloyDBListInstancesTest, runAlloyDBGetClusterTest, runAlloyDBGetInstanceTest, runAlloyDBGetUserTest, and TestWaitToolEndpoints. However, several tests (runAlloyDBListUsersTest, runAlloyDBGetClusterTest, runAlloyDBGetInstanceTest, runAlloyDBGetUserTest) were only partially refactored, resulting in compilation errors due to undefined resultStr variables and incorrect usage of the old body.Result field. Additionally, error handling for io.ReadAll is missing in runAlloyDBListClustersTest and runAlloyDBListInstancesTest, which should be addressed for robustness.

[Yuan325]

why are there TestAlloyDBCallTool vs TestAlloyDBMCPReadEndpoints?

[Yuan325]

Could you double-check the comments across all test cases? Just want to make sure the updates carried over to all of them. Thank you!

[Yuan325]

Are we expecting that all the want will be within got?

Can we keep the original check?: I think in here, we want to make sure that got doesn't return more cluster than it originally should.

var got []string
for _, cluster := range clustersData.Clusters {
	got = append(got, cluster.Name)
}

sort.Strings(got)
sort.Strings(tc.want)

if !reflect.DeepEqual(got, tc.want) {
	t.Errorf("cluster list mismatch:\n got: %v\nwant: %v", got, tc.want)
}

[Yuan325]

Suggested change

	wantContains string
	wantContentErr string

want vs wantContains feels very confusing.
If you can update for the other tests as well that'll be great, ty!

[Yuan325]

Suggested change

	wantContains string
	wantContentErr string

[Yuan325]

we might be able to just remove this check since tc.want will always be >0.

[Yuan325]

we should be able to remove this check since tc.want is always >0

[Yuan325]

Suggested change

	wantContains string
	wantContentErr string

[Yuan325]

might not need to check this based on the test cases that we have.

[Yuan325]

Suggested change

	wantContains string
	wantContentErr string

[Yuan325]

won't need to check this.

Suggested change

if tc.want != nil {

[Yuan325]

won't need to check this.